<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .container{
            height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
        }
        .clickChange{
           width: 150px;
           height: 150px;
           background-color: aqua;
           border-radius: 50%; 
           transition: 0.5s;
        }
        /* 开始按钮 */
        .start_btn{
            position: absolute;
            width: 50px;
            height: 50px;
            background-color: aquamarine;
            transition: 0.4s;
        }
        /* 结束按钮 */
        .end_btn{
            position: fixed;
            top: 10px;
            left: 10px;
            width: 50px;
            height: 50px;
            background-color: aquamarine;
            display: none;
        }
        #click_01:checked ~ .clickChange{
           width: 100vw;
           height: 100vh;
           background-color: red;
           border-radius: 0; 
        }
        #click_01:checked ~ .start_btn{
            width: 20px;
            height: 20px;
            background-color: aquamarine;
            border-radius: 50%;
            display: none;
        }
        #click_01:checked ~ .end_btn{
            display: block;
        }

    </style>
</head>
<body>
        <!-- 点击圆圈充满整个屏幕 -->  
    <div class="container">
        <input type="checkbox" name="" id="click_01" hidden>
        <label for="click_01" class="start_btn">s_Btn</label>
        <label for="click_01" class="end_btn">e_Btn</label>
        <div class="clickChange"></div>
       
    </div>
</body>
</html>
